Template:Selected anniversaries/April 20: Difference between revisions
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||1865: Astronomer Angelo Secchi demonstrates the Secchi disk, which measures water clarity, aboard Pope Pius IX's yacht, the L'Immaculata Concezion. | ||1865: Astronomer Angelo Secchi demonstrates the Secchi disk, which measures water clarity, aboard Pope Pius IX's yacht, the L'Immaculata Concezion. | ||
||1871: Slavoljub Eduard Penkala born ... engineer, invented the mechanical pencil. Pic. | |||
File:Curie_and_radium_by_Castaigne.jpg|link=Radium (nonfiction)|1902: Pierre and Marie Curie refine [[Radium (nonfiction)|radium chloride]]. | File:Curie_and_radium_by_Castaigne.jpg|link=Radium (nonfiction)|1902: Pierre and Marie Curie refine [[Radium (nonfiction)|radium chloride]]. | ||
Revision as of 07:26, 3 February 2019
1548: Mathematician, astronomer, and alleged time-traveller Petrus Apianus publishes Cosmographicus furatis, his magisterial treatise on crimes against astronomical constants.
1653: Oliver Cromwell dissolves the Rump Parliament.
1790: Mathematician and detective Johann Friedrich Pfaff uses partial differential equations of the first order Pfaffian systems to track and erase the Forbidden Ratio.
1902: Pierre and Marie Curie refine radium chloride.
1903: Leeches in Tempest prognosticator go on strike, demanding "less tempest and more prognostication."
1932: Mathematician Giuseppe Peano dies. He did pioneering work in mathematical logic and set theory.
1933: Art critic and alleged time-traveller The Eel is caught in the act of cracking a safe.
1945: Mathematician Georg Feigl dies. He worked on the foundations of geometry and topology, studying fixed point theorems for n-dimensional manifolds. Feigl was one of the initial authors of the Mathematisches Wörterbuch.
1960: Industrialist, public motivational speaker, and alleged crime boss Baron Zersetzung calls the upcoming Bay of Pigs Invasion "a rock-solid business investment which is certain to generate handsome returns for early investors."
1961: Failure of the Bay of Pigs Invasion of US-backed Cuban exiles against Cuba.
1962: Traces of Clandestiphrine residue are detected at the Bay of Pigs, raising questions about CIA involvement with transdimensional drugs.
2018: Chromatographic analysis of Two Creatures 6 unexpectedly reveals previously unknown color.